如何解决此“未找到子字符串”错误？

Question

所以，我希望用户输入他的名字和姓氏，然后这两个词将每隔一个字母相互替换。

def translate(ime,prez):
    translated_i = ""
    translated_p = ""
    if len(ime) >= len(prez):
        for letter in prez:
            if prez.index(letter) != 0:
                translated_p = translated_p + ime[prez.index(letter)]
                if prez.index(letter) >= len(prez)-1:
                    translated_i = translated_i + ime[prez.index(letter):]
                else:
                    translated_i = translated_i + prez[ime.index(letter)]
        else:
            translated_p = translated_p + letter
            translated_i = translated_i + ime[prez.index(letter)]
    elif len(prez) > len(ime):
        for letter in ime:
            if ime.index(letter) != 0:
                translated_i = translated_i + prez[ime.index(letter)]
                if prez.index(letter) >= len(prez)-1:
                    translated_p = translated_p + prez[ime.index(letter):]
                else:
                    translated_p = translated_p + ime[prez.index(letter)]
            else:
                translated_i = translated_i + letter
                translated_p = translated_p + prez[ime.index(letter)]
    return translated_i + " " + translated_p
    x = input("Name: ")
    y = input("Last name: ")

    print(translate(x,y))

但是有一个错误说：'ValueError: substring not found'

Answer 1

根据文档，如果未找到子字符串， index函数会引发ValueError 。 因此，您可以将代码包装在try/except块中，而不是检查if ime.index(letter) != 0 。 例如：

try:
    letter_index = ime.index(letter)
    # your logic if substring found
except ValueError as ex:
    # logic if substring not found

Answer 2

它为我工作

代码：

def translate(ime,prez):
    translated_i = ""
    translated_p = ""
    if len(ime) >= len(prez):
        for letter in prez:
            if prez.index(letter) != 0:
                translated_p = translated_p + ime[prez.index(letter)]
                if prez.index(letter) >= len(prez)-1:
                    translated_i = translated_i + ime[prez.index(letter):]
                else:
                    translated_i = translated_i + prez[ime.index(letter)]
        else:
            translated_p = translated_p + letter
            translated_i = translated_i + ime[prez.index(letter)]
    elif len(prez) > len(ime):
        for letter in ime:
            if ime.index(letter) != 0:
                translated_i = translated_i + prez[ime.index(letter)]
                if prez.index(letter) >= len(prez)-1:
                    translated_p = translated_p + prez[ime.index(letter):]
                else:
                    translated_p = translated_p + ime[prez.index(letter)]
            else:
                translated_i = translated_i + letter
                translated_p = translated_p + prez[ime.index(letter)]
    return translated_i + " " + translated_p

x = input("Name: ")
y = input("Last name: ")

print(translate(x,y))

SS：

Answer 3

我复制粘贴了您的代码，除了缩进错误之外，一切正常。 我建议您将缩进修复为：

def translate(ime,prez):
    translated_i = ""
    translated_p = ""
    if len(ime) >= len(prez):
        for letter in prez:
            if prez.index(letter) != 0:
                translated_p = translated_p + ime[prez.index(letter)]
                if prez.index(letter) >= len(prez)-1:
                    translated_i = translated_i + ime[prez.index(letter):]
                else:
                    translated_i = translated_i + prez[ime.index(letter)]
        else:
            translated_p = translated_p + letter
            translated_i = translated_i + ime[prez.index(letter)]
    elif len(prez) > len(ime):
        for letter in ime:
            if ime.index(letter) != 0:
                translated_i = translated_i + prez[ime.index(letter)]
                if prez.index(letter) >= len(prez)-1:
                    translated_p = translated_p + prez[ime.index(letter):]
                else:
                    translated_p = translated_p + ime[prez.index(letter)]
            else:
                translated_i = translated_i + letter
                translated_p = translated_p + prez[ime.index(letter)]
    return translated_i + " " + translated_p
x = input("Name: ")
y = input("Last name: ")

print(translate(x,y))

并将其复制粘贴到另一个文件中。 如果您遇到另一个错误并且您使用的不是 IDLE 的文本编辑器，请尝试 IDLE 中的代码。